as is often the
问题描述：
as is often the
答
事常如是
答
在句首它就是插入语：As is often the case, Mary comes here in her car. Mary开车来这里，这是常常发生的事情.
在句尾，把as换成which,就成了定语从句：
Mary comes here in her car, which is often the case.
答
你这个说法其实是后面那个As it often the case对的前面那个错的，没有这个说法的
答
这是常有的事。
情况常常如此
答
这是常有的事.
as／which is often the case (with) ...
此句型意为"…是常有的情形".这是当的 as 以全体当先行词的